Identification of multiple cracks in beams under bending
TL;DR: In this paper, a local compliance matrix of two degrees of freedom, bending in the horizontal and the vertical planes is used to model the rotating transverse crack in the shaft and is calculated based on the available expressions of the stress intensity factors and the associated expressions for the strain energy release rates.
About: This article is published in Mechanical Systems and Signal Processing.The article was published on 2006-10-01. It has received 95 citations till now. The article focuses on the topics: Crack tip opening displacement & Stress intensity factor.
Citations
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TL;DR: In this paper, the strain energy release rate (SERR) theory is applied to a rotating crack and gives good results, and different methods of crack identification are presented as well as those for multi-crack identification.
170 citations
TL;DR: In this paper, the authors summarize the different studies on double/multi-cracks and to note the influences, identification methods in vibration structures such as beams, rotors, pipes, etc.
142 citations
TL;DR: A new method for cracks detection in beams is proposed by using the slope of the mode shape to detect cracks, and by introducing the angle coefficients of complex continuous wavelet transform, which demonstrates that the proposed method outperforms the existing method of wavelets transform of the modes shape with real wavelets.
Abstract: : A new method for cracks detection in beams is proposed by using the slope of the mode shape to detect cracks, and by introducing the angle coefficients of complex continuous wavelet transform. This study is aimed at detecting the location of the nonpropagating transverse crack. A series of beams with cracks that are simulated by rotational springs with equivalent stiffness are analyzed. The mode shape and the slope of this lumped crack model are calculated. Through complex continuous wavelet transform of the slope of the mode shape using Complex Gaus1 wavelet (CGau1), the locations of cracks are detected from the modulus line and the angle line of wavelet coefficients. By comparison, the singularity is much more apparent from the angle line of complex continuous wavelet transform. This demonstrates that the proposed method outperforms the existing method of wavelet transform of the mode shape with real wavelets. Also, this method can detect cracks in beams with different boundary conditions. The influence of crack locations and crack depth on crack detection is discussed. Finally, the noise effect is studied. Through the multiscale analysis, the locations of cracks may be detected from the angle of wavelet coefficients.
93 citations
Cites background from "Identification of multiple cracks i..."
...Chasalevris and Papadopoulos (2006) analyzed the dynamic behavior of a shaft with two cracks that were characterized by depth, position, and relative angle....
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TL;DR: The aim of this paper is to present a review on recent studies and investigations done on cracked rotor to provide all the methodologies adopted by various researchers to investigate a cracked rotor.
Abstract: Fatigue crack is an important rotor fault, which can lead to catastrophic failure if undetected properly and in time. Study and Investigation of dynamics of cracked shafts are continuing since last four decades. Some review papers were also published during this period. The aim of this paper is to present a review on recent studies and investigations done on cracked rotor. It is not the intention of the authors to provide all literatures related with the cracked rotor. However, the main emphasis is to provide all the methodologies adopted by various researchers to investigate a cracked rotor. The paper incorporates a candid commentary on various methodologies. The paper further deals an extended Lagrangian formulation to investigate dynamics of cracked rotor.
69 citations
Cites result from "Identification of multiple cracks i..."
...Papadopoulos and Dimarogonas [20] have analyzed for the local crack compliance for a six-degree-of-freedom crack beam segment....
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...Unlike the previous studies, in Chasalevris and Papadopoulos [33] each crack is characterized by its depth, position, and relative angle....
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TL;DR: In this article, the dynamic response of a cracked rotor near its critical speed has been computed via a numerical method to investigate the influence of nonlinear breathing of the crack and that of the imbalance orientation angle β on the stability, critical speed and peak response of the rotor.
64 citations
References
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TL;DR: In this paper, a crack in a structural member introduces a local flexibility that affects its vibration response, and the crack will open and close in time depending on the rotation and vibration amplitude.
1,080 citations
15 Jul 2002
TL;DR: The Illustrated Wavelet Transform Handbook: Introductory Theory and Applications in Science, Engineering, Medicine and Finance as discussed by the authors is a comprehensive overview of wavelet transform applications in science, engineering, medicine and finance.
Abstract: (The correction deals with the fact that the complex Morlet wavelet has a non-zero See for example: The Illustrated Wavelet Transform Handbook: Introductory. The Illustrated Wavelet Transform Handbook: Introductory Theory and Applications in Science, Engineering, Medicine and Finance. CRC Press, Boca Raton. Tags: synchrosqueezing time-frequency analysis wavelet transform P.S. Addison, The Illustrated Wavelet Transform Handbook: Introductory Theory.
942 citations
Book•
01 Dec 1993
TL;DR: In this paper, the authors introduce the idea of joint probability distributions and average for linear systems and their response to random vibrational signals. But they do not discuss the relationship between these distributions and the average.
Abstract: 1. Introduction To Probability Distributions And Averages. 2. Joint Probability Distributions, Ensemble Averages. 3. Correlation. 4. Fourier Analysis. 5. Spectral Density. 6. Excitation - Response Relations For Linear Systems. 7. Transmission Of Random Vibration. 8. Statistics Of Narrow Band Processes. 9. Accuracy Of Measurements. 10. Digital Spectral Analysis I: Discrete Fourier Transforms. 11. Digital Spectral Analysis II: Windows And Smoothing. 12. The Fast Fourier Transform. 14. Application Notes. 15. Multi-Dimensional Spectral Analysis. 16. Response Of Continuous Linear Systems To Stationary Random Excitation. 17. Discrete Wavelet Analysis.
855 citations
TL;DR: In this article, the authors proposed a non-destructive testing method for crack identification, which requires amplitude measurements at two positions of the structure only and is applicable to all one-dimensional structures.
721 citations
TL;DR: In this paper, a review of the field of the dynamics of cracked rotors is presented, including the modeling of the cracked part of the structure and finding different detection procedures to diagnose fracture damage.
Abstract: Propagating fatigue cracks can have detrimental effects on the reliability of rotating machinery. An early crack warning can considerably extend the durability of these very expensive machines, increasing their reliability at the same time. Vibration monitoring as a means of detecting crack initiation has been receiving much interest. A detailed study of the vibrational behavior of cracked rotating shafts, therefore, is an important problem for engineers working in the area of the dynamics of machines. This article presents a review of the field of the dynamics of cracked rotors, including the modeling of the cracked part of the structure and finding different detection procedures to diagnose fracture damage. The material should be helpful to scientists and researchers working in this area or planning to work in it in the future. Since the study of nonrotating, cracked structural elements obviously is relevant to the cracked rotor problem, the review can also be a basis for discussing the dynamics of cracked beams and columns.
387 citations